1. Field of the Invention
The present invention relates generally to medical methods and devices for accessing body lumens and in particular to methods and apparatus for identifying ductal orifices in human breasts and accessing the ducts through the identified orifices.
Breast cancer is the most common cancer in women, with well over 100,000 new cases being diagnosed each year. Even greater numbers of women, however, have symptoms associated with breast diseases, both benign and malignant, and must undergo further diagnosis and evaluation in order to determine whether breast cancer exists. To that end, a variety of diagnostic techniques have been developed, the most common of which are surgical techniques including core biopsy and excisional biopsy. Recently, fine needle aspiration (FNA) cytology has been developed which is less invasive than the surgical techniques, but which is not always a substitute for surgical biopsy.
A variety of other diagnostic techniques have been proposed for research purposes. Of particular interest to the present invention, fluids from the breast ducts have been externally collected, analyzed, and correlated to some extent with the risk of breast cancer. Such fluid collection, however, is generally taken from the surface of the nipple and represents the entire ductal structure. Information on the condition of an individual duct is generally not provided. Information on individual ducts can be obtained through cannulation and endoscopic examination, but such examinations have been primarily in women with nipple discharge or for research purposes and have generally not examined each individual duct in the breast.
Since breast cancer usually arises from a single ductal system and exists in a precancerous state for a number of years, endoscopy in and fluid collection from individual breast ducts holds great diagnostic promise for the identification of intermediate markers. Much of the promise, however, cannot be realized until access to each and every duct in a patient's breast can be assured. Presently, ductal access may be obtained by a magnification of the nipple and identification of ductal orifice(s) using conventional medical magnifiers, such as magnification loupes. While such magnified examination is relatively simple, it cannot be relied on to identify all orifices. Moreover, the ductal orifices can be confused with other tissue structures, such as sebaceous glands and simple keratin-filled caruncles of the nipple. Thus, before ductal techniques can be further developed for diagnostic, research, or other purposes, it will be useful to provide methods and apparatus which facilitate identification of ductal orifices to distinguish them from other orifices, and allow subsequent ductal access in selected and/or all ducts in each breast.
2. Description of the Background At
Publications by the inventors herein relating to breast duct access include Love and Barsky (1996) Lancet 348: 997-999; Love (1992) “Breast duct endoscopy: a pilot study of a potential technique for evaluating intraductal disease,” presented at 15th Annual San Antonio Breast Cancer Symposium, San Antonio, Tex., Abstract 197; Barsky and Love (1996) “Pathological analysis of breast duct endoscoped mastectomies,” Laboratory Investigation, Modem Pathology, Abstract 67. A description of the inventors' breast duct access work was presented in Lewis (1997) Biophotonics International, pages 27-28, May/June 1997.
Nipple aspiration and/or the introduction of contrast medium into breast ducts prior to imaging are described in Sartorius (1995) Breast Cancer Res. Treat. 35: 255-266; Sartorius et al. (1977) “Contrast ductography for the recognition and localization of benign and malignant breast lesions: An improved technique,” in: Logan (ed.), Breast Carcinoma, New York, Wiley, pp. 281-300; Petrakis (1993) Cancer Epidem. Biomarker Prev. 2: 3-10; Petrakis (1993) Epidem. Rev. 15: 188-195; Petralkis (1986) Breast Cancer Res. Treat 8: 7-19; Wrensch et aL (1992) Am. J. Epidem. 135: 130-141; Wrensch et al. (1990) Breast Cancer Res. Treat. 15: 39-51; and Wrensch et al. (1989) Cancer Res. 49: 2168-2174. The presence of abnormal biomarkers in fine needle breast aspirates is described in Fabian et al. (1993) Proc. Ann. Meet. Am. Assoc. Cancer Res. 34: A1556. The use of a rigid 1.2 mm ductoscope to identify intraductal papillomas in women with nipple discharge is described in Makita et aL (1991) Breast Cancer Res. Treat. 18: 179-188. The use of a 0.4 mm flexible scope to investigate nipple discharge is described in Okazaki et aL (1991) Jpn. J. Clin. Oncol. 21: 188-193. The detection of CEA in fluids obtained by a nipple blot is described in inayama et aL (1996) Cancer 78: 1229-1234. Delivery of epithelium-destroying agents to breasts by ductal cannulation is described in WO 97/05898.